Nationalism is fueled by the same sort of need for common identity by which religion is fueled. Just as the creeds and dogmas that bind (the literal meaning of “religion,” by the way), are given their reality only by the aggregate effect of many individuals’ perceptions of their reality or “truth,” so too “nations” are given their reality only by the aggregate effect of people imagining they are real things outside of our minds.
Why? Because people obtain an adaptive advantage by banding together into groups and working together. They do so by constructing a shared “social reality.” That social reality has its power by virtue of individuals not recognizing that it is, despite its shared nature through language and culture, still a purely subjective phenomenon based on judgments and intellectual categories whose only residence is in our minds.
I think that we have evolved a social “instinct,” on which “morality” and culture builds itself by use of symbols.
Religion is a cultural identity not based on family, though it takes advantage of family relationships for its implantation as part of an individual’s identity. Of course, we already have common identity with family. Kinship relations already carry an emotional commonality and have existed in human culture since long before organized “religion.” Indeed, we see highly organized societies such as ant colonies that are organized around kinship relationships. Ants of the same species will frequently fight each other, identifying the sides by the colony through some sort of chemical recognition of colonial kinship.
“Religion” is a method of extending cultural identity beyond kinship. The “secular” methods of nationalism, race distinctions, social class distinctions and other, similar cultural phenomena are just a more effective version of the same method to create a recognition of shared identity between persons for whom a kinship identity is not recognized.
This method allows people to be made obedient to the will of larger groups and accomplish large-scale projects that the kinship identity or the village of the more primitive folk religions cannot. The evolution of organized “religion” (and here I include nationalism, racism, and other cultural phenomena that often work in conjunction with what we commonly recognize as “religion” and which use a similar method) is that these larger, better organized groups of obedient people were and are better able to compete for resources against groups of humans whose common identity is limited to kinship relations, or the loosely defined village folk religions. A powerful social instinct to adopt and conform to the predominant social reality has been selected by natural processes and passed along as features of the identities better adapted to competing for control of resources.
Social reality works as an adaptive strategy in the following manner:
First: Practically speaking we can accomplish much more when we work together compared to what we can accomplish attempting to meet our needs and further our biological success as lone animals. The bigger the group, the larger in scale our adaptive and survival strategies can be.
Second: Working together requires that I subjugate what I perceive as personal interests to the greater good of the group of which I am a part, otherwise we never achieve the advantage of the group. Thus, natural processes have selected humans with a tendency to want to attach themselves to a group identity and govern behavior by attaching certain standards of coduct to the social instinct we have evolved.
Third: If I recognize that I don’t personally obtain any advantage by subjugating my interest to that of the group, I will not do so. Thus we begin to see the evolution of morality and rights not as a recognition of the rights of others but as a gamble that by respecting the rights of others I will attain respect for my own rights to function within the group and attain a share of profit from the group’s success. Biologically and socially we function with an innate faith that others will honor our sacrifices and we will not be taken advantage of by individuals who use our sacrificed will against us. Or if we do, the law will punish the dissenters in order restore our confidence in the socio-biological wisdom of losing individuality by functioning as part of a large group.
Fourth: A common, group “identity” is created to which I shall ascribe my self so that it becomes difficult for me to separate the success of the group from the success of “me,” and thereby make it less likely that I will rebel from the demands of the group when the fruits of the progress are shared unequally. A set of laws are created to punish dissenters and encourage my confidence and security within the group identity. Since the larger group structures cannot depend as much on the biological commonality of the kin group (the natural recognition that my genetic material is advanced by favoring those who share some of it with me), we evolve ever more complicated group identities to encompass progressively less biologically related individuals into group cooperation. The biologically recognized kin groups becomes the tribe associated together by a tribal religion. Tribes become villages and cities who associate with one another through a more organized and less individualistic religion that supercedes invidual regional tribal religious identities - thus religious dogma is born and a set of evolving symbols to which we are conditioned to associate our innate moral and social impulses. Collections of villages and cities becomes nations encompassing multiple religious dogmas - thus nationalism is born (with an accompanying set of symbols that we are conditioned to respond to), and a group identity to which the individual, tribal and dogmatic wills are to be subject.
Fifth: This places one in a state of cognitive dissonance with regard to the group identity or culture. However, that state can be broken by overly prolonged periods of feeling one is not benefitted by adherence to the group identity. If an individual feels as though he or she does not have a stake in society - that individual will become a dissenter to the group identity and will not abide by its rules including the honoring of the gamble others make in trading rights for progress. They are the “criminals,” “rebels,” “terrorists” and “radicals.”